Switch mechanism



Aug. 25, 1931. o. s. JENNINGS SWITCH MECHANISM Filed Nov. 19 1927 2 Sheets-Sheet INVENTOR O//L/er SJ'enn/ngs,

ATT'ORNEY Aug. 25,1931. 0.5. JENNlNGs 1,820,704

SWITCH MECHANISM Filed Nov. 19, 1927 2 Sheets-Sheet, 2

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A'TTORNEY Patented Aug. 25, 1931 UNITED` STATES PATENT OFFICE OLIVER S. JENNINGS, OF MANSFIELD, OHIO, ASSIGNOR TO WESTINGHOUSE ELECTRIC &

MANUFACTURING COMPANY,

A CORPORATION OF PENNSYLVANIA s'wirori MECHANISM Application filed November 19, 1927. Serial No. 234,380.

My invention relates to switch mechanism and particularly to switch mechanism of the enclosed safety type wherein interlock mechanism is provided between the door and the switch for maintaining the door in closed position while the switch is closed and for preventing closing movement of the switch while the door is opened.

An object of my invention is to provide a Iswitch mechanism of the interlocked type wherein the latch is provided for the door that is released by the switch only when the switch is in full open position and to provide a latch for the operating handle that is actuated by the door of the housing, the latch serving to retain the switch operating handle in open position until it has been displaced by the dooi` and when the door is in full closed position.

A further object of my invention is to provide a switch mechanism having the above-noted characteristics wherein the various parts of the interlock mechanism may be made of pressed metal and wherein the switch mechanism assembly is inexpensive to manufacture.

These and other objects that will be made throughout the further description of my invention are attained by means of the apparatus hereinafter described and illustrated in the accompanying drawings, wherein Figure 1 is a front elevational view of an enclosed safety switch embodying features of my invention.

5 Fig- 2 is a longitudinal view through the switch mechanism taken along the line 11-11 of Fig. 1.

Fig. 3 is a longitudinal view similar to that shown in Fig. 2, showing the operating parts in the positions that they occupy when the switch and operating handle therefor is iii open position; and

Fig. 4 is a similar longitudinal sectional view through an enclosed switch having a modified form of switch interlock.

Referring to the drawings, the switch mechanism includes a sheet metal housing 6 having side walls 7 and 8, end walls 9 and a .bottom wall y11. The housing is provided 'v with a cover 12 that is pivotally attached to the housing by means of hinge rivets 13. The cover 12 is provided with a flange 14; that extends over the exterior front face of t-he housing 6 as indicated in Figs. 2 and 3.

The switch mechanism comprises an insulating base 15 upon which is mounted hinge jaws 16 and contact jaws 17 for receiving switch blades 18 that are pivoted to the hinge jaws 16. The switch blades 18 are of the usual knife blade type and are adapted to be simultaneously operated by means of a bent operating bail 19 which constitutes a crank arm that is pivoted in the side walls 7 and 8, the end thereofl that is journaled in the side wall 7 extending exteriorly of the housing for receiving an operating handle 21 upon which the handle is pivoted.

The switch mechanism and the operating handle illustrated are similar to the corresponding devices disclosed in a copending application, Serial No. 659,259, filed by Hubert K. Kraiitz September 25, 1924, now Patent No. 1,606,801 and assigned to the Westinghouse Electric & Manufacturing Company. The details of the operating handle constitute no part of the present invention with the exception of changes in construction required to adapt it for cooperation with certain interlock mechanism to be hereinafter described. It is, therefore, not deemed necessary to particularly describe the construction of the switch mechanism and operating mechanism except to specify that the opera-ting handle is connected to the operating bail or crank arm 19 by means of a lost motion connection and that the switch is moved to open and closed positions with a snap action by a spring in the operating handle, after the operating handle has been moved a predetermined distance between its extreme positions of movement. The operating handle 21 constitutes a hollow casing having an open side adjacent the said wall 7 of the housing, the cas-l ing serving to enclose the operating mechanism.

In order to releasably retain the door 12 in closed position so long as the switch is in closed position, a latch member 22 is pivy' of the handle.

otally mounted upon the crank arm 19 adjacent the inner side of side wall 7, the latch being provided with a shoulder 23 that engages a latch clip 24 that is secured to the inner side of the door 12 as indicated in Figs. 2 and 3. The latch 22 is normally biased in the closed position shown in Fig. 2 by means of a spring 25 that is attached at one end to anextension 2O on the latch 22 and at the other end to a switch interlock latch 26 that is pivoted to the side wall 7 and which will be hereinafter more fully described.

The latch 22 is provided with extension 27 that extends normal to the plane of the latch 22 and across the path of movement of the crank arm 19. When the crank arm and switch are moved to the full open position with a snap action, the arm strikes the extension 27 on the latch 22 and rotates it in a clockwise direction until the shoulder 23 clears the latch clip 24. The door may then be moved to open position.

In order to prevent closure of the switch and the operating handle therefor, the interlock latch 26 is provided with an outwardly extending shoulder plate 28 that projects through an opening 29a in the side wall 7. The spring 25 normally biases the interlock latch26 to the position shown in broken lines in Fig. 2. The shoulder plate 28 eX- tends across the path of movement of the flange 14 on the cover 12 and, therefore, is moved to the releasing position shown in full lines in Fig. 2 when the cover is in the closed position. The side wall of the operating handle 21 is provided with notches 29 and 31 for the purpose of providing clearance spaces through which the projecting shoulder plate 28 of the interlock latch 26 moves whenthe operating handle and thefshoulder plate are in certain operating positions.

Referring to Fig. 3, it will be noted that when the operating handle21 is in the open position shown, and assuming that the cover is open and the interlock latch 26 is in its outer position shown in the dotted lines, the shoulder plate 28 lies within the hollow operating handle and prevents closing movement thereof. Should an attempt be made to move the operating handle 26 to the closed position while the cover is open, the shoulder plate 28 will engage the side wall of the handle 21 interiorly thereof at a point near the outer end of. the notch29 in the wall In order to close the operating handle and the switch, it is first necessary to close the cover so that the .flange 14 thereof will depress the interlock latch 26 to the position shown in full lines in F ig. 3, thus disposing the shoulder plate 28 in a position that it registers with the notch 29 in the handle and thus clearing the handle and permitting closing movement thereof.

Should it be desired to close the switch when the cover is open for the purpose of test, the interlock latch 26 may bedepressed by means of a screw. driver or like implement which may engage the latch 26 at a point within the housing.

By reason of the interlock and latch mechanism above described,`it is apparent that the cover is retained in closed position until the switch has been moved to full open position and that the switch cannot be closed until the cover has been moved to full closed position;

With reference to the construction disclosed in Fig. 4, the switch operating mechanism is identical to that previously described, the only difference residing in a modified interlock construction which cooperates with a different part of the operating handle.

The hollow operating handle 21 is provided with a semi-circular portion 32 that is of greater diameter than the widest portion of the handle, thus providing shoulders 33 and 34 which are of certain utility in connection with the 4operating mechanism disclosed in the aforesaid copending application. It is desired to lprovide an interlock latch 26 that cooperates with the shoulders 33 and 34 and which functions similar to the latch 26 illustrated in Figs. 1, 2 and 3.

The latch 26 is pivoted to the side wall 7 of the housing and is provided with a shoulder plate 28 that projects exteriorly of the housing through an opening 29a in the sidewall 7. The interlock latch is provided with an extension 35 that engages the innerside of the door 12 and is yieldingly biased to the latched position indicated in broken lines in Fig. 4 by means of a spring 25 that is attached at one end to the extension 35 and at the other end to the door latch 22.

l/Vhen the latch 26 is in the latched position indicated by the broken lines, the shoulder plate 28 is disposed beneath the shoulder 33 on the operatinghandle 21 and prevents counterclockwise or closing movement thereof.` lVhen the door 12 is moved to the closed position, it engages the extension 35 ofthe interlock latch 26 and moves the latch to the position shown in full lines in Fig. 4, wherein the shoulder plate 28 clears the shoulder 33 on the operating handle 21, and permits closing movement thereof. The door latch 22 is similar to the latch disclosed in Figs. 1, 2 and 3 with the exception that theV spring 25 is attached differently, but in such manner that it functions to yieldingly retain the latch in closed position and the interlock latch 26 'in the latched position.

While I have illustrated but two embodiments of my invention, it will be apparent to those skilled in the art that various changes, modifications, substitutions, additions and omissions may be made in the apparatus illustrated without departing from the spirit and scope of my invention as set forth in the appended claims.

I claim .as my invention:

1. Switch mechanism comprising a casing, a movable cover for the casing, a switch within the casing movable to open and closed positions, an operating handle for the switch exterior of the casing, and an interlock for the switch and cover for preventing closing movement of the switch while the door is open comprising a movable latch mounted within the casing and extending exteriorly thereof through an opening in the casing for engaging the handle exteriorly of the casing and movable clear thereof by the cover when the latter is in closed position and means'connected to the latch interiorly of the casing for yieldingly holding the latch f in latching position.

2. Switch mechanism comprising a casing, a movable cover for the casing, a switch within the casing movable to open and closed positions, a latch for the cover movable to open position by the switch, and a separate latch for the'switch movable to open position by the cover.

3. Switch mechanism comprising a casing, a movable cover for the casing, a switch within the casi ng movable to open and closed positions, a latch for the cover movable to open positionby the switch, a separate latch for the switch movable to open position by the cover, and a spring connecting the latches whereby they are yieldingly biased to closed positions.

4. Switch mechanism comprising a casing, a movable cover for the casing, a switch within the casing movable to open and closed position, an operating handle for the switch having a lost motion connection thereto, a latch for the cover movable to open position by the switch and a separate latch for the handle movable to open position by the cover.

In testimony whereof, I have hereunto subscribed my name this 3rd day of November, 1927.

OLIVER S. JENNINGS. 

